In the manufacture of semiconductor devices, micro-processing by lithography using a photoresist has been carried out. The micro-processing is a processing method comprising forming a thin film of a photoresist on a semiconductor substrate such as a silicon wafer or the like, irradiating actinic rays such as ultraviolet rays through a mask pattern on which a pattern for a device is depicted, developing it to obtain a photoresist pattern, and etching the substrate using the photoresist pattern as a protective film, thereby forming fine unevenness corresponding to the pattern on the surface of the substrate. On the other hand, in recent progress: in high integration of devices, there has been a tendency that shorter wavelength actinic rays are being used, i.e., ArF excimer laser beam (193 nm) has been taking the place of KrF excimer laser beam (248 nm). However, in these photolithography processes, there occurs a problem that dimension accuracy of the photoresist pattern is lowered by an influence of standing wave due to reflection of exposure light from the substrate or an influence of random reflection of exposure light due to unevenness on the substrate. Accordingly, it has been widely studied to provide an anti-reflective coating between the photoresist and the substrate (Bottom Anti-Reflective Coating, BARC) in order to resolve the problem.
These anti-reflective coatings are often formed by use of a heat crosslinking composition in order to prevent intermixing with a photoresist applied thereon. Thus, the resulting anti-reflective coatings become insoluble in developers for photoresist and the removal of the anti-reflective coatings prior to semiconductor substrate processing is required to be carried out by dry etching (see, for example Patent Document 1). However, the photoresist is removed simultaneously with the removal of the anti-reflective coating by dry etching. Therefore, there causes a problem that it becomes difficult to secure film thickness of the photoresist required for substrate processing. This becomes a very serious problem in case where thin photoresists are used for the purpose of improvement in developing property.
In addition, an ion implantation in the manufacture of semiconductor devices is a process for introducing impurities into a semiconductor substrate by use of a photoresist pattern as a template, and in order to avoid providing damage on the surface of the substrate, pattern formation of photoresist cannot be performed by dry etching process. Therefore, anti-reflective coating requiring removal by dry etching could not be formed as an underlayer of photoresist in photoresist pattern formation for ion implantation. The conventional photoresist pattern used as a template in the ion implantation process has a wide line-width and thereby was little affected by an influence of standing wave due to reflection of exposure light from the substrate or an influence of random reflection of exposure light due to unevenness on the substrate. Thus, problems by reflection have been resolved by use of a dye-containing photoresist or an anti-reflective coating as an upper layer of photoresist. However, with the recent miniaturization, a fine pattern begins to be required also for photoresist used in ion implantation process, and an anti-reflective coating as an underlayer of photoresist is being required.
Under these circumstances, it has been desired to develop an anti-reflective coating that can be dissolved in a developer for photoresist and removed simultaneously with photoresist by development. On the other hand, anti-reflective coatings that can be removed simultaneously with photoresist by development have been studied until now (see, for example Patent Documents 2, 3, 4, 5 and 6). However, they were not enough in applicability for fine processing, formed pattern form, and the like.
Patent Document 1: U.S. Pat. No. 6,156,479 (2000)
Patent Document 2: JP Patent No. 2686898 (1997)
Patent Document 3: JP-A-9-78031 (1997)
Patent Document 4: JP-A-11-72925 (1999)
Patent Document 5: WO 03/057678 pamphlet
Patent Document 6: WO 03/058345 pamphlet